With worldwide shipments of 216.2 million units during the first quarter, smartphones grabbed 51.6% of the total mobile phone market. According to IDC's data, this is the first time that hardware makers have shipped more smartphones than feature phones on a global basis. It's a significant milestone.

Phone makers shipped 418.6 million devices during the quarter, which was up 4% compared to the year-ago quarter (402.4 million), but down compared to the previous quarter (483.2 million). The first quarter typically sees a downturn in sales following the holiday quarter, so these numbers follow the seasonal trends.

The overall mobile market may have grown only 4%, but smartphone shipments improved 41.6% year-over-year, jumping from 152.7 million in 2012 to 216.2 million in 2013. Smartphone shipments dipped just 5.1% from the fourth quarter of 2012, which saw shipments of 227.8 million.

The worldwide transition from feature phones to smartphones has been a long time coming. Mature markets such as North America and Europe have shipped more smartphones than feature phones for a while now. It is emerging markets such as India and others in the Asia-Pacific Rim that are driving the push to smartphones.

"Phone users want computers in their pockets," said Kevin Restivo, senior research analyst with IDC. "The days where phones are used primarily to make phone calls and send text messages are quickly fading away. As a result, the balance of smartphone power has shifted to phone makers that are most dependent on smartphones."

That would be Samsung and Apple.

Samsung shipped more smartphones -- 70.7 million devices -- than any other vendor during the first quarter. It increased shipments by 60.7% percent compared to the year-ago period, and grabbed 32.7% of the smartphone market. Samsung was also the world's largest supplier of all mobile phones, with shipments climbing 22.9% from 93.6 million last year to 115 million during the first quarter. Samsung commands 27.5% of the entire mobile phone market.

When it comes to smartphones, Apple ranks a distant second to Samsung. The company shipped 37.4 million iPhones during the first quarter, giving it 17.3% of the smartphone market. Apple improved shipments only 6.6% year-over-year, and actually lost market share. Apple held 23% of the smartphone market during the first quarter of 2012.

LG, Huawei and ZTE round out the top five smartphone makers during the first quarter, with shipments of 10.3 million, 9.9 million and 9.1 million, respectively. All three companies saw significant year-over-year growth. In fact, LG was the biggest mover in the entire smartphone market, increasing shipments 110.2%. Huawei's growth wasn't far behind, improving 94.1% year-over-year. ZTE saw about half as much growth, improving shipments 49.2% from the year-ago period.

Looking at the entire cellphone market, Nokia ranked second after Samsung. According to IDC, Nokia shipped 61.9 million devices during the first quarter, representing a precipitous 25.1% drop in shipments from the year-ago period. Nokia managed to hold onto 14.8% of the mobile phone market during the first quarter.

Apple followed in third place with its shipments of 37.4 million iPhones. Apple laid claim to 8.9% of the overall phone market.

LG and ZTE round out the top five mobile phone makers, with shipments of 15.4 and 13.5 million, respectively. Those shipments gave LG and ZTE ownership of 3.7% and 3.2% of the cellphone market, respectively. Conspicuously absent from the top five phone makers are companies such as Motorola, Sony and BlackBerry.

The broader battle between Samsung and Apple is only going to intensify. Samsung may well extend its lead over the next six months. The Galaxy S4, its flagship device for the year, reaches the U.S. and other markets this month. Apple is not expected to offer a new iPhone until the fall, giving Samsung four or five months to build its user base.